THE INFLUENCE AND CONTROL OF SHEARING ON THE DEVELOPMENT OF THE OPTICAL ANISOTROPY OF ORGANIC MATTER

Not far from western Baisha town of Luyan county in western Hunan, there is a shallow oil-bearing brittle-ductile shear zone, in which the organic matter has striking optical anistrophy, with R_o,min values ranging from 0.34% to 0.81%, R_o,med values from 1.01% to 1.84%, and R_o,max values from 2.52% to 3.20%, and the maximum bireflectance amounting to 87%, the R_o,max axis of the optical anisotropy ellipsoid being paralled to S foliation. The shear stress is considered to have an influence and control on the development of optical anisotropy of the organic matter.